Optimized operation method for live replacement of insulator

Abstract

The invention relates to the technical field of power maintenance, in particular to an optimized operation method for live replacement of an insulator. According to the method, through six core steps of scheme making, tool preparation, personnel in place, insulator replacement, function verification and operation ending, the deterioration degree of the insulator is quantitatively evaluated in combination with detection means such as infrared temperature measurement and ultraviolet imaging, and the heating risk is calculated by using load current. And operation safety is guaranteed through measures such as insulation tool correction testing, safety distance monitoring and equipotential transfer protection. Meanwhile, optimization means such as RFID tool management, temperature difference coefficient detection and the like are introduced, so that the problems of fuzzy risk assessment, insufficient safety control and disordered tool management in the traditional live-line insulator replacement operation are solved, and the standardization of the operation process, the precision of risk control and the traceability of the operation quality are realized. The insulator replacing device is suitable for insulator replacing operation of a line with the voltage class of 110 kV to 500 kV and above.

Description

Technical Field

[0001] This invention relates to the field of power maintenance technology, and in particular to an optimized operation method for replacing insulators while the circuit is energized. Background Technology

[0002] Insulators are critical insulation components in power transmission lines. Long-term exposure to the natural environment makes them susceptible to pollution, aging, and electrical breakdown, leading to a decline in their insulation performance and threatening the safe and stable operation of the power grid. Traditional insulator replacement often involves power outage operations, which not only affect power supply reliability but also cause economic losses. With increasing user demands for power supply continuity, live-line insulator replacement is gradually becoming a necessary technical means. However, existing live-line replacement methods still have many shortcomings in terms of tool selection, safety distance control, insulator condition assessment, and operational efficiency. There is an urgent need for a systematic, quantitative assessment, and refined operational optimization method to improve operational safety and efficiency. Summary of the Invention

[0003] To overcome the above shortcomings, this invention provides an optimized operation method for live insulator replacement, aiming to solve the problems existing in current live insulator replacement methods in terms of tool selection, safety distance control, insulator condition assessment, and operation efficiency.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] An optimized operation method for replacing insulators under energized conditions includes the following steps:

[0006] 1. Plan Formulation

[0007] The insulator type, string structure, tower type, conductor arrangement, and grounding distance were confirmed on-site for the target line section. Infrared thermography and ultraviolet imaging were used to detect the degree of deterioration of the insulators to be replaced and the operating status of surrounding equipment. The deterioration coefficient was then used to... The formula for quantifying the degree of insulator degradation is:

[0008]

[0009] in This is the highest infrared temperature measured on the insulator. The ambient temperature of the work environment. This is the highest standard operating temperature for insulators of the same type. The equivalent voltage of the leakage current detected by ultraviolet imaging. This is the rated voltage of the insulator. The weighting factor for the effect of temperature is 0.8 (0.8 when humidity > 80%, 0.6 when humidity < 50%). If it is determined that immediate replacement is necessary, Replacement may be postponed at this time.

[0010] Calculate the heating risk value using real-time load current. The formula is:

[0011]

[0012] in This represents the real-time load current of the line. This is the equivalent resistance of the insulator. To estimate the operation time, The specific heat capacity of the insulator is 850 J / (kg·℃) for ceramic and 800 J / (kg·℃) for glass. For the mass of a single insulator, To allow for a temperature rise of 20°C; when Fever can affect safety. Sometimes it is necessary to adjust the working hours or reduce the load.

[0013] Develop a live-line work instruction manual, clearly defining the division of labor among personnel, a list of tools and equipment, emergency plans, and risk control measures; apply for a work permit from the dispatching department and confirm the reclosing operation has been discontinued.

[0014] 2. Tool Preparation

[0015] Prepare specialized insulated load-bearing tools, clamps, lead screws, backup protective ropes, shielding suits, insulated operating rods and tension sensors, gap monitors, laser rangefinders, and infrared thermal imagers.

[0016] Perform a visual inspection on all insulating tools and calculate the insulation resistance under actual operating conditions. The formula is:

[0017]

[0018] in: The insulation resistance was measured under standard laboratory conditions. For laboratory temperature testing; The operating temperature at the site; The relative humidity at the work site; For laboratory testing of relative humidity; This is a temperature correction factor; This is a humidity correction factor; it is for tools with voltage levels of 220kV and below. Or for tools with voltage levels of 500kV and above, At that time, the insulating tools were deemed qualified.

[0019] Set up tool storage areas, personnel standby areas, and emergency rescue passages near the work tower, and use warning tape to isolate non-working personnel; install temporary grounding electrodes to ensure that the personnel access passages are reliably grounded to the same potential.

[0020] 3. Staff in place

[0021] Ground electricians install backup protective ropes on the side of the conductors, securing them to reliable anchor points on the crossarms to prevent accidental wire slippage. Equipotential bonding workers wear full protective suits and approach the conductors via insulated ladders or insulated bucket trucks. The bucket trucks are equipped with dual locking devices for horizontal displacement and vertical lifting, automatically locking when the distance is less than a safe threshold. Distance warning indicator lights on the control panel (green for safety, yellow for approaching the threshold, and red for exceeding the threshold) assist in controlling the movement speed.

[0022] The guardian shall monitor the safe distance between the human body and live or grounded conductors in real time. The distance shall meet the requirements of not less than 1.0m for 110kV lines, not less than 1.8m for 220kV lines, and not less than 3.0m for 500kV lines, and the distance between the human body and the grounded conductor shall not be less than 0.4m.

[0023] Equipotential bonding personnel approach the conductor by "crossing two insulators and short-circuiting no more than three insulators" and use a special equipotential bonding transfer rod (with a spherical conductive contact with a diameter of not less than 30mm and a silver-plated surface) to contact the conductor; the transfer rod has a built-in current sensor to monitor the transfer current in real time, and automatically cuts off the circuit and alarms when the peak value exceeds 10A.

[0024] 4. Removal of old insulators and installation of new insulators

[0025] Equipotential bonding personnel use specialized clamps to lock the hardware at both ends of the insulator, and gradually transfer the conductor load to the insulator load-bearing tool using a lead screw. The rated load-bearing capacity of the specialized clamps is not less than 1.2 times the maximum load of the conductor, the lead screw adjustment accuracy is not less than 5mm, and the conductor displacement during the load transfer process is controlled within 50cm. After confirming that the original insulator string is completely unloaded using a tension sensor, the spring pins, ball head hanging rings, and other connecting parts are disassembled, and the old insulator is smoothly moved out of the string position and sent to the ground via a transfer rope.

[0026] The new insulators, which have passed the power frequency withstand voltage test beforehand, are hoisted and the hardware is connected in the original structural sequence to ensure that the bowls are facing the same direction and the locking pins are in place; the tension of the load-bearing tools is slowly released so that the new insulator string can bear the full conductor load.

[0027] 5. Functional verification and gap check

[0028] Personnel responsible for equipotential bonding inspected all connection points of the new insulator strings to ensure they were secure and that no components were missing. A laser rangefinder or gap rod was used to verify the electrical clearance between the conductors and the tower, crossarms, and other phase conductors, ensuring it met the requirements of electrical safety regulations. An infrared thermal imager was used to scan the newly installed insulators and connection points to calculate the temperature difference coefficient. :

[0029]

[0030] For the first The highest temperature of a new sheet insulator; The average of the highest temperatures of all new insulators; when At that time, it was determined that there was no abnormal fever; when If the insulator is found to be overheating, the connection point needs to be checked or the insulator needs to be replaced.

[0031] 6. End of assignment

[0032] Personnel at equipotential points must return to the ground along the original path after disengaging from the conductor, and are strictly prohibited from crossing low-potential areas in the opposite direction. An RFID tag identification system is used for automatic registration and verification of tools and equipment, comparing them against the tool and equipment list. If any tools are missing, the name, model, and last used location of the missing tool are displayed. Recovered tools undergo visual inspection and are photographed for archiving. Tools with damage or aging issues are automatically marked as requiring maintenance, and a maintenance work order is generated. Temporary protective devices and grounding wires are removed, and an application is made to the dispatch department to restore the automatic reclosing function of the line. The supervisor records all data throughout the operation, including operation duration, temperature monitoring data, and tool usage.

[0033] The present invention has the following beneficial effects:

[0034] Improve operational safety and the accuracy of risk control

[0035] By introducing detection methods such as infrared thermography and ultraviolet imaging, the degree of insulator degradation (degradation coefficient Kd) is quantitatively assessed, and the heating risk value (Rh) is calculated in conjunction with real-time load current, enabling accurate prediction of operational risks. Simultaneously, strict safety distance monitoring, equipotential transfer protection measures, and insulated tool condition correction tests effectively reduce the probability of accidents such as electric shock and equipment damage, ensuring the safety of personnel and equipment.

[0036] Optimize tool management and usage efficiency

[0037] The adoption of an RFID tag identification system for automatic registration, verification, and status tracking of tools has enabled intelligent and traceable tool management. Combined with condition correction testing of insulation resistance and visual inspection photography for archiving, the misuse of faulty tools is effectively prevented, tool preparation and recycling efficiency is improved, and management chaos is reduced.

[0038] Enhance quality verification and failure prevention capabilities

[0039] During the functional verification phase, the electrical clearance was checked using a laser rangefinder, and the temperature difference coefficient (ΔTcoef) was detected using an infrared thermal imager to ensure that the newly installed insulators were reliably connected and free from abnormal overheating. This multi-dimensional quality verification mechanism promptly identified potential defects, preventing operational failures caused by improper installation and improving the quality and long-term reliability of the replacement work.

[0040] Improve operational efficiency and economy

[0041] By optimizing operating procedures and introducing efficient tools, the operation time has been significantly shortened. Live-line working methods have avoided power outages and reduced maintenance costs, thereby improving the economy of power grid operation and the continuity of power supply. Attached Figure Description

[0042] Figure 1 This is a flowchart of an optimized operation method for replacing insulators under energized conditions, as proposed in this invention. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] 1. Implementation Preparation

[0045] The target line is a 220kV transmission line with XP-70 (ceramic) insulators, a single string of 13 pieces, a straight tower, horizontal conductor arrangement, and a grounding distance of 2.5m.

[0046] Ambient temperature on the day of operation relative humidity There was no precipitation, strong winds, or other severe weather, which met the meteorological requirements for live-line work.

[0047] 2. Plan Formulation

[0048] The highest temperature of the insulator to be replaced was measured using an infrared thermometer. The highest standard operating temperature for insulators of the same model Ultraviolet imaging detected the equivalent voltage of the leakage current. Insulator rated voltage Due to humidity Between 50% and 80%, the weighting factor for the effect of temperature is taken. .

[0049] Deterioration coefficient calculation: , , it is determined that the insulator needs to be replaced immediately.

[0050] Calculation of the heating risk: The dispatching department provides the real-time load current , the equivalent resistance of the insulator , the estimated operation duration ; The specific heat capacity of the porcelain insulator , the single-piece mass , the allowable temperature rise . Substituting into the formula, we get , , it is determined that the influence of heating is within the safe range.

[0051] Formulate an operation instruction manual to clarify the division of labor among 1 guardian, 2 equal-potential operators, and 2 ground electricians; the tool list includes 220kV insulating bearing tools, special fixtures, screw jacks (adjustment accuracy 5mm), backup protection ropes, full sets of shielding clothing, tension sensors, laser rangefinders, etc.; the emergency plan covers the disposal procedures for emergencies such as electric shock and tool breakage; apply for operation permission from the dispatching department and confirm that the reclosing is withdrawn.

[0052] 3. Tool preparation

[0053] Under the standard environment of the laboratory, the insulation resistance of the 220kV insulating bearing tool ; Substitute into the formula to calculate the insulation resistance under the actual working conditions , and it is determined to be qualified.

[0054] Set up a tool placement area 5m north of the operation tower, a personnel standby area 3m west of it, and reserve a 2m-wide emergency rescue passage on the east side, and isolate it with red warning tapes; install a temporary grounding electrode at the grounding electrode of the operation tower, and the measured value of the grounding resistance is 5Ω, which meets the requirements.

[0055] 4. Staff take their positions

[0056] The ground electrician fixes one end of the backup protection rope on the cross arm reliable anchor point on the conductor side, and connects the other end to the conductor, and tightens the protection rope to a slightly stressed state.

[0057] The equal-potential operator wears a full set of shielding clothing and approaches the conductor by riding an insulating boom truck; when the boom truck moves horizontally to a distance of 2.0m from the conductor, the warning indicator light turns yellow; when it continues to move to 1.8m, the double locking device is automatically activated, prohibiting the boom from getting closer.

[0058] Adopt the method of "crossing two insulators and short-circuiting no more than three insulators", and use a special equal-potential transfer rod (contact diameter 35mm, surface silver-plated) to contact the conductor; during the transfer process, the current sensor shows the current peak value of 8A ≤ 10A in real time, without an alarm signal, and the equal-potential transfer is successfully achieved.

[0059] 5. Removal of old insulators and installation of new insulators

[0060] The equipotential bonding personnel used XP-70 special clamps to lock the hardware at both ends of the insulator to be replaced. The rated load capacity of the clamps is 15kN (the maximum load of the conductor is 12kN, 15kN ≥ 12kN × 1.2 = 14.4kN); the conductor load was slowly transferred through the lead screw, and the tension sensor showed that the original insulator string load dropped from 12kN to 0, confirming that the load was completely unloaded.

[0061] Remove the spring pins and ball head rings from the old insulators, and smoothly move the old insulators out of the cascade position. Send them to the ground via an insulated transfer rope, where ground personnel receive them and mark them as "to be tested".

[0062] The new XP-70 insulators, which have undergone a power frequency withstand voltage test (test voltage of 420kV, lasting for 1 minute without breakdown), are hoisted and connected in the original structural sequence. Ensure that the bowls face outwards from the line and that the locking pins are fully inserted. The screw tension is slowly released, and the tension sensor shows that the load on the new insulator string increases from 0 to 12kN, confirming that the load has been completely transferred.

[0063] 6. Functional verification and gap check

[0064] The equipotential bonding personnel checked the spring pins and ball head rings of the new insulator strings one by one to confirm that all connections were secure and no parts were missing.

[0065] The minimum distance between the conductor and the tower was measured to be 2.2m and the minimum distance between the conductor and the crossarm was 1.9m, both of which are greater than the safety clearance requirement of 220kV lines (1.8m).

[0066] Infrared thermal imagers scanned the new insulator string and measured the highest temperatures of the 13 insulator pieces as 30℃, 31℃, 29℃, 30℃, 31℃, 29℃, 30℃, 31℃, 29℃, 30℃, 31℃, 29℃, and 30℃, respectively; the average values ​​were calculated. Temperature difference coefficient of each insulator All within ±3.3%, No abnormal fever was detected.

[0067] 7. End of assignment

[0068] Personnel at equipotential levels returned to the ground via a boom truck following the original route, without crossing the low-potential area in the opposite direction.

[0069] The RFID tag identification system scanned all tools and equipment, showing that all 15 tools in the list had been recovered without any missing items; a visual inspection revealed a slight scratch on the surface of an insulated operating rod, which the system automatically marked as "pending repair" and generated a repair work order.

[0070] Remove the temporary grounding electrode and backup protective rope, and apply to the dispatch department to restore the reclosing function; the supervisor records the data of the entire operation process, with a total operation time of 1.5 hours, which is 0.5 hours shorter than the traditional operation time.

[0071] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An optimized operation method for replacing insulators under live conditions, characterized in that: Includes the following steps: S1 Plan Development: Conduct on-site surveys of the target line section to confirm the insulator type, string structure, tower type, conductor arrangement, and grounding distance; use infrared thermography, ultraviolet imaging, and other methods to detect the degree of deterioration of the insulators to be replaced and the operating status of surrounding equipment; based on the survey data, develop detailed live-line work instructions, clarifying personnel assignments, tool and equipment lists, emergency plans, and key risk point control measures; Apply for a work permit from the dispatching department, confirm the reclosing is off, and obtain real-time load current data to assess the impact of heat generation; S2 Tool Preparation: Prepare dedicated insulated load-bearing tools, clamps, lead screws, backup protective ropes, shielding suits, insulated operating rods, tension sensors, and gap monitors; conduct visual inspection and insulation resistance testing on all insulated tools before use; set up tool placement areas, personnel standby areas, and emergency rescue passages near the work tower, and use warning tape to isolate non-working personnel; install temporary grounding electrodes to ensure reliable grounding of personnel access passages at equipotential levels; S3 personnel in position: Ground electricians first install backup protective ropes on the side of the conductor and fix them to reliable anchor points on the crossarm to prevent accidental derailment; equipotential workers wear full protective suits and approach the conductor along a predetermined path using an insulated rope ladder or insulated bucket truck; during the approach, a supervisor monitors the safe distance between the human body and live conductors and grounding conductors in real time; equipotential workers use the method of "crossing two insulators and short-circuiting no more than three insulators" to finally contact the conductor and achieve equipotential transfer; S4 Old Insulator Removal and New Insulator Installation: Equipotential bonding personnel use special clamps to lock the hardware at both ends of the insulator, and gradually transfer the conductor load to the insulator load-bearing tool using a lead screw; after confirming that the original insulator string is completely unloaded using a tension sensor, the spring pins, ball head hanging rings, and other connecting parts are disassembled, and the old insulator is smoothly moved out of the string position and sent to the ground via a transfer rope; the pre-inspected and qualified new insulator is hoisted, and the hardware is connected in the original structural sequence, ensuring that the cups are aligned and the locking pins are in place, and the tension of the load-bearing tool is slowly released so that the new insulator string can bear the full conductor load; S5 Function Verification and Gap Check: Equipotential personnel check whether each connection point of the new insulator string is tight and whether any parts are missing; use a laser rangefinder or gap bar to check whether the electrical clearance between the conductor and the tower body, crossarm and other phase lines meets the requirements of the regulations; scan the newly installed insulator and connection points with an infrared thermal imager to confirm that there is no abnormal heating phenomenon. S6 Operation completed: Equipotential personnel should disengage from the conductor along the original path and return to the ground, and are strictly prohibited from crossing the low-potential area in the opposite direction; ground personnel should retrieve all tools and equipment, count their quantity, and confirm that no items are left on the line; remove temporary protective devices and grounding wires, and restore the automatic reclosing function of the line; the supervisor should record the data of the entire operation process.

2. The optimized operation method for replacing insulators under energized conditions according to claim 1, characterized in that: In S1, the degradation coefficient of the insulator is calculated based on infrared thermometry data. To quantitatively assess the degree of degradation: ， The highest infrared temperature measured for the insulator; The ambient temperature of the work environment; This is the standard maximum temperature for insulators of the same type during normal operation. This is the equivalent voltage corresponding to the insulator leakage current detected by ultraviolet imaging. This refers to the rated voltage of the insulator. The temperature influence weighting coefficient ranges from 0.6 to 0.8, adjusted according to the ambient humidity: 0.8 for humidity > 80% and 0.6 for humidity < 50%. When it is determined that the insulator needs to be replaced immediately; when If the condition is deemed mildly deteriorated, replacement can be postponed.

3. The optimized operation method for replacing insulators under energized conditions according to claim 1, characterized in that: In S1, the heating risk value of the insulator is calculated using the real-time load current obtained from the dispatching department. The formula is: ， In the formula: This refers to the real-time load current of the line. This is the equivalent resistance of the insulator; For the estimated operation time; For the specific heat capacity of the insulator, 850 J / (kg·℃) is used for porcelain insulators and 800 J / (kg·℃) is used for glass insulators; This refers to the mass of a single insulator piece; For the allowable temperature rise of the insulator, take 20℃; when When the fever is deemed to be within a safe range, it is determined that the impact is within acceptable limits. If necessary, the operating time should be adjusted or a reduction in load current should be requested.

4. The optimized operation method for replacing insulators under energized conditions according to claim 1, characterized in that: In S2, the insulation resistance test data of the insulating tools are corrected and calculated to obtain the insulation resistance under actual working conditions. : ， in: The insulation resistance was measured under standard laboratory conditions. For laboratory temperature testing; The operating temperature at the site; The relative humidity at the work site; For laboratory testing of relative humidity; This is a temperature correction factor; This is a humidity correction factor; it is for tools with voltage levels of 220kV and below. Or for tools with voltage levels of 500kV and above, At that time, the insulating tools were deemed qualified.

5. The optimized operation method for replacing insulators under energized conditions according to claim 1, characterized in that: In S3, the safe distance between the human body monitored by the guardian and the live conductor must meet the requirements of the power safety work regulations, which are no less than 1.0m for 110kV lines, no less than 1.8m for 220kV lines, and no less than 3.0m for 500kV lines; during the equipotential transfer process, the distance between the human body and the grounding conductor shall be no less than 0.4m.

6. The optimized operation method for live insulator replacement according to claim 1, characterized in that: In S3, when equipotential workers approach the conductor using an insulated bucket truck, the bucket truck is equipped with a dual locking device for horizontal displacement and vertical lifting. When the distance between the bucket truck and the live conductor is less than the safety threshold, the locking device automatically activates, preventing the bucket from continuing to move towards the live conductor. In addition, a distance warning indicator is installed on the bucket truck's control panel. Green indicates that the safe distance is sufficient, yellow indicates that the safe threshold is approaching, and red indicates that the safe threshold is exceeded, assisting the operator in controlling the movement speed.

7. The optimized operation method for live insulator replacement according to claim 1, characterized in that: In S3, when equipotential personnel perform equipotential transfer, they use a special equipotential transfer rod. The head of the transfer rod has a spherical conductive contact with a diameter of not less than 30mm and a silver-plated surface to reduce contact resistance. During the transfer, the transfer current is monitored in real time by a current sensor built into the transfer rod. The peak current must not exceed 10A. If the threshold is exceeded, the transfer rod will automatically cut off the conductive path to prevent the risk of electric shock and send an alarm signal to the supervisor.

8. The optimized operation method for live insulator replacement according to claim 1, characterized in that: In S4, the rated load-bearing capacity of the special clamp shall not be less than 1.2 times the maximum load of the conductor; the adjustment accuracy of the lead screw shall not be less than 5mm, and the displacement of the conductor during the load transfer process shall be controlled within 50cm; the new insulator shall undergo a power frequency withstand voltage test before hoisting, and the test voltage shall meet the standard requirements of the corresponding voltage level insulator.

9. The optimized operation method for replacing insulators under energized conditions according to claim 1, characterized in that: In S5, temperature data is collected using an infrared thermal imager, and the temperature difference coefficient of the insulator is calculated. The formula is: ， For the first The highest temperature of a new sheet insulator; The average of the highest temperatures of all new insulators; when At that time, it was determined that there was no abnormal fever; when If the insulator is found to be overheating, the connection point needs to be checked or the insulator needs to be replaced.

10. An optimized operation method for replacing insulators under energized conditions according to claim 1, characterized in that: In S6, an RFID tag identification system is used when recycling tools to automatically register and verify all insulating tools entering and leaving the work area. The system identifies the identity information of each tool through RFID tags and automatically compares it with the tool list during recycling. If any tool is missing, the system immediately displays the name, model and last used location of the missing tool. At the same time, the system performs a visual inspection and takes photos for archiving. If any tool is found to be damaged or aged, the system automatically marks it as pending maintenance and generates a maintenance work order to prevent the reuse of problematic tools.

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